Ticking sound coming from air con compressor

[lmhdex]

Hi

I was told it's normal to hear this ticking sound whenever the thermostat adjusts the temperature but lately the sound has been occurring very frequently.  I normally set my temp to abt 22-23 degrees.

Even when I switched to a lower temp, say 18%,

With the ticking sound comes a hissing sound like a release of gas, which I think is the air compressor working.

Is this normal or is this a problem with the air con?

[kelvin]

ur hissing sound is it coming from the driver side dashboard area?if yes ,then ur air con systerm has a leak some where,maybe is the coil.

[lmhdex]

The hissing sound doesn't occur as frequently as the ticking sound.....so is the ticking sound caused by the leak?

[kelvin]

did you really hear where this ticking sound came from,is it inside or outside? 

[lmhdex]

The sound comes from under the hood.

When I switch off the air con, no more sound, so I'm very sur eit's the air con.